The first Hadrosaurus fossil was found in New Jersey
in 1858 by William Parker Foulke. Actually excavated and named by anatomist Joseph Leidy, Hadrosaurus is significant
because it was the first American dinosaur to be described. The skeleton excavated was nearly complete. Today, New Jersey
has adopted Hadrosaurus as their state fossil.

Marx's Hadrosaurus is interesting for several reasons. First, one must wonder
why they chose to do a figure of this dinosaur in addition to the similar (yet now obsolete) Trachodon. He is quite different than Trachy, though, the pose being sort of a sitting down and 'waving howdy' one. He's also outdated,
and most likely modeled after this picture by Charles Knight, a famous early 20th-century artist who specialized in painting prehistoric animals.

More contemporary depictions of Hadro (as well as other 'duck-billed dinos) show
him walking along on all fours, only raising up to walk on his hind legs occasionally.